Rotating sprinklers are often employed on traveling irrigation machines such as center-pivot machines, lateral-move machines, etc. Typically, the sprinklers are attached to the lower end of a rigid water supply pipe (or a flexible water supply hose) descending from a lateral boom on a traveling irrigation machine or from a stationary overhead water manifold as commonly used in greenhouses and riding arenas. One such rotating sprinkler is built around a quick-change nozzle and adapter system as described in U.S. Pat. No. 5,415,348. The rotating sprinkler described in the '348 patent has proven to be reliable and durable, but has drawbacks stemming from the fact that the water exiting the water-deflection plate has to flow across three stationary struts that support the deflection plate downstream of the nozzle. While the struts are narrow and formed with sharp leading edges to minimize disruption of the stream, stringy material in the water can loop about one or more of the struts and build up to the point of significantly disrupting the stream, or even stalling rotation of the water-deflection plate. In addition, the struts leave dry, narrow “shadows” in the wetted pattern. It has also been found that a noticeable amount of water passing over the struts does not spray outward but, rather, drips down directly underneath the sprinkler. In addition, the diameter of the water-deflection plate is limited by the radial placement of the struts, which sometimes results in geometry on the water-deflection plate that limits the radius-of-throw of the unit.
It is also desirable to provide a sprinkler that maintains a substantially constant speed of rotation while accommodating line pressure and nozzle size variations, whether of the braked or free-spinning type.
There remains a need, therefore, for a rotating sprinkler that addresses these problems in a reliable and cost-effective manner.